Crankcase breather hose

Does anyone know the inside diameter of the crankcase breather braided hose that connects between the cyclone and air filter?

I'm looking at maybe disconecting this hose and fitting and re-routing with filter, and then blocking the hole at the induction hose end

I dont have the car to hand, but would like to look online to see if suitably sized filters and blocking plugs are available

Thanks

Ade